A coin sorting machine with active sorting is one example of a device according to the above. Active sorting means that each separating station in the machine has a movable member which by receiving control signals can be caused to switch between two different positions; a first, deactivated position in which the movable member assumes a retracted position with respect to the transport path and thus does not affect a passing coin, and a second, activated position in which the movable member assumes a position which intrudes upon the transport path and thus will separate a passing coin from the transport path. Electromagnetic solenoids are often used in the separating stations, wherein the control signals are applied voltages or currents at appropriate levels and the movable member is the movable core of the solenoid, and/or a deflector coupled to this movable core. Which separating station that is to be activated so as to sort off an individual coin is determined by a coin sensor and a controller, which detect suitable physical parameters for the coin (such as conductivity, permeability, diameter and/or thickness), determine a coin type (such as denomination, valid/false) and supply control signals to the correct separating station at the appropriate moment, i.e. at a correct timing so that the particular individual coin will be separated when the movable member of the separating station assumes its activated position, without thereby separating other coins than the intended one (for instance such coins that have another denomination and therefore shall be separated by another separating station).
One example of a coin sorting machine according to the above is disclosed in WO 99/33030, which in its illustrated embodiment has 10 separating stations, each having a solenoid, distributed along a circular transport path. Another example of a coin sorting machine for active sorting, having a linear rather than a circular transport path, is disclosed in WO 87/07742.
Another type of coin sorting machines are such that operate with a passive sorting technique. Here, instead of separating stations that can be activated/deactivated, purely passive arrangements are used for separating the coins at respective positions along the transport path. In a common type of passive coin sorting machines the coins are caused to roll down a sloping sorting rail, where sorting knives are arranged at successively decreasing heights above the transport path, wherein coins with the largest diameter are separated by the first sorting knife in the transport direction, and then coins having the second largest diameter are separated by the next sorting knife, and so on. Another common type of passive coin sorting machine instead uses a rotary carrier device which transports the coins in a circular transport path by way of a dragging movement over a baseplate, in which coin falling openings of successively increasing size have been arranged.
There are several drawbacks with the passive coin sorting machines described above. For instance, mechanical measures are required in the machine (replacement of baseplate, height position adjustment of sorting knives, etc) so as to adapt the machine for use in a coin system with another currency, etc. Another drawback is mechanical wear and tear of coins as well as sorting mechanism. In addition, some passive coin sorting machines have a limited sorting capacity.
Coin sorting machines with active sorting technique make it possible to avoid or at least mitigate the problems given above and are therefore both interesting and popular. Furthermore, they can be made compact.
By choosing components for the sorting mechanism and the coin sensor with high quality and accuracy, and by carefully programming the controller of the coin sorting machine, a coin sorting machine with active sorting technique can be made to exhibit an astonishingly high sorting capacity and a very good accuracy (low error rate). Of course, the active sorting technique has certain technical limitations as regards how fast the separating stations can switch between activated and deactivated positions. Therefore, during the operation of a coin sorting machine with active sorting technique, situations with so called coin trains are repeatedly occurring. A coin train is a sequence of successive coins, which even if they can be detected and determined in type individually by the coin sensor and the controller, they are too close to each other in distance to be sorted off individually by the separating stations. Such situations with coin trains can be handled appropriately by programming the controller to handle a coin train in different ways depending on its nature: whether all coins contained in the coin train are destined to the same destination or to different destinations, whether the coin train contains invalid coins that are to be returned (known as reject coins, etc), and so on.
Since coin sorting machines with active sorting technique contain movable components in the separating stations, there is a common need to increase the efficiency of the machine (the sorting capacity), at the same time reducing the wear and tear of the movable components, reducing the heat generated from their operation as well as limiting the generated noise to a reasonable level. By handling certain coins as a coin train rather then individual coins, improvements may be achieved in these areas.